Small molecules that modulate protein complexes have transformed cell biology and oncology, yet few chemical starting points exist to probe protein-protein interactions. To expand this space, we developed molecular COUPLrs, elaborated small molecules flanked by two cysteine‑reactive warheads. Using CONNECT, an integrated chemical proteomic platform that identifies proteins and complexes amenable to coupling, we revealed 171 targetable protein classes, including mutant‑selective complexes and assemblies not traditionally addressed by small molecules. We then optimized a COUPLr against the oncogenic fusion EML4‑ALK. This compound engages EML4‑ALK by binding its EML4 domain, remodeling protein dynamics, disrupting downstream signaling, and inducing proteasome‑mediated degradation of the fusion. Finally, we show that FDA‑approved drugs can be converted into COUPLrs to degrade their targets, indicating that this modality can endow existing therapeutics with new functional properties. Overall, molecular COUPLrs offer an unbiased framework to discover, characterize, and pharmacologically exploit protein complexes.
Diane Yang, S. Harry, H. Chong et al.· Cancer Discovery· 0 citations
Ligand dimerization represents a powerful strategy to enhance avidity, potency, and selectivity. Leveraging the natural-product molecular glue rocaglamide (RocA), we identified BisRoc, a dimeric rocaglate ligand that potently and durably suppresses translation and exhibits greater specificity across a cancer cell line panel than the monomeric RocA. CRISPRi screening revealed that BisRoc activity is influenced by cellular context, including IFITM-mediated uptake, ABC-type efflux transporters, and the translation initiation factor eIF4A2. Mechanistic studies showed that the paralogs eIF4A1 and eIF4A2 are differentially sensitive to BisRoc-induced dimerization. Owing to the presence of multiple binding sites on RNAs, BisRoc-bridged eIF4A-RNA motifs assemble into higher-order complexes that promote stress-granule formation more efficiently than monomeric RocA. Given the widespread multivalency of RNA-RBP interactions, this ligand dimerization strategy may be extended to modulate the higher-order assembly of other RNA-binding proteins.
Jie Liu, Megan K. Moore, Kevin Lou et al.· ACS Central Science· 0 citations
